BIOS System Customization

Boot options are one of the most welcome innovations in the modern BIOS. They allow you to select the order in which your computer searches for a boot device. In the original PC model, computers always tried to boot from floppy disk before hard disk, an expedient that insured you could always use a boot floppy should you accidentally corrupt your hard disk. Eliminating the check for a boot floppy saves expensive seconds in the already-too-long boot process.

Modern BIOSs go further than merely sidestepping the floppy disk search, however. They allow you to choose which devices in your system are allowed to act as boot drives and in which order they are checked for boot files. The basic Award BIOS, for example, gives you an option for selecting “boot sequence” that gives your hard disk priority over your floppy disk drive. In fact, most of today’s BIOSs have multiple boot-device support that allows you to choose which of your hard disks acts as the first boot drive. In theory, you can have multiple operating systems on different disks and choose which one to use by selecting the boot order. The feature gives every computer a multi-boot option that once was controlled by operating systems.

Boot options are, in fact, one BIOS setup function that has not been pre-empted by Windows. The boot device choices must be made before Windows (or any operating system) loads, so the BIOS code is the only code in your system that’s active. The following list includes boot options used by most popular BIOS setup systems; no one system will offer all of them:

After power failure sets what you want your computer to do when power is restored after an interruption. You can set your system to switch on and reboot or stay off. Select the former if you want your computer always to be ready and waiting for you. Choose the latter to play it safe, so your computer doesn’t keep trying to switch back on during brief periods of power restoration or so that you know the power has been off.

On modem ring selects if you want your computer’s modem to answer incoming calls even if it has shifted to its standby mode. Select this mode and a signal from your modem will wake up your computer from its catnap.

On LAN selects if you want your computer to switch itself on (system can be totally shut off) when it receives a “magic packet” across your network. When you select this mode, it allows your computer to be constantly active in your network but also to power-down to save electricity.

Scan user flash area, when selected, tells the BIOS to check for additional firmware code that you may have added in addition to the standard BIOS. Choose this option only if the documentation for an update for your BIOS tells you that you must activate it.

First boot device selects which of the potential boot drives connected to your computer will be tried first to find bootstrap code. Typically this option allows you to select a list of boot devices that will be checked, in the order you list, for boot information. The first device on the list with valid boot code will be the one to actually boot your system.

Hard drive allows you to choose the order in which your hard drives (when you have multiple drives installed in your computer) are scanned for boot files. Typically, you will make a list of the drives with the first (or uppermost) drive being the one first scanned. Depending on the BIOS, if the first drive on the list does not have a valid boot file, your system may stop and issue an error message, or it may scan the next drive in the list until it finds a valid boot file. In any case, if you put a different operating system on each drive, you can select which operating system to use merely by putting its drive first in the list. This option works in conjunction with the first boot device option.

Removable devices allows you to choose devices other than hard disks as the boot device for your computer. In systems with this option, you list the removable devices in the order you want them checked for valid boot files. Typically your floppy disk drive and CD drive will appear in the list. This option works in conjunction with the first boot device option.

Quick Power-On Self-Test or Memory check speeds up the boot-up process so you need not wait as long as your computer boots up. The idea is that computer circuits are so reliable (or their failure so obvious) there’s no need to check them. Of course, modern computers that do not use parity-checking of their memories are susceptible to crashing from memory errors, and a memory check is your only prevention against such problems. Skip the memory check or enable the quick POST procedure if you’re more impatient than worried.

Modern systems allow you to enter setup only during boot-up because the information you enter during setup changes what the BIOS tests and how it configures your computer. The BIOS needs to know the setup stuff before it completes. Moreover, altering some of the setup parameters while your computer is operating can cause it to crash.

Use of this site is governed by our Terms of Use and Privacy Policy. Copyright 1996-2016 Ziff Davis, LLC.PCMag Digital Group All Rights Reserved. ExtremeTech is a registered trademark of Ziff Davis, LLC. Reproduction in whole or in part in any form or medium without express written permission of Ziff Davis, LLC. is prohibited.